U.S. congressional staffers, who visited North Korea's nuclear facilities last week, are in Seoul briefing South Korean officials - but are refusing to publicly disclose what they saw. The visit comes as China says a long-awaited second round of multi-party talks on the North Korean nuclear standoff could be held in February.

Members of the private American delegation are being tight-lipped about details of their visit to North Korea's Yongbyon nuclear complex last week. They are the first group of foreigners to gain access to North Korea's nuclear programs since U.N. monitors were expelled a year ago.

Two members of the delegation, U.S. congressional staffers, were briefing South Korean officials in Seoul Monday. They will only say it is too soon to draw any conclusions about the state of North Korea's weapons development.

The Washington Post newspaper reported the group saw recently reprocessed plutonium, a key component of nuclear bombs. North Korea says it has produced nuclear weapons and U.S. experts believe that to be true.

North Korea has offered to freeze its program in exchange for aid and other concessions from the United States. Washington says North Korea must dismantle its nuclear capabilities before aid will be considered.

The issue has reportedly been a major stumbling block to a second round of talks involving North Korea, the United States, Japan, South Korea, Russia and China. A first round of nuclear talks in Beijing in August ended only with agreement to meet again, but North Korea has yet to confirm a date.

Media in Tokyo quote Japanese officials in Beijing as saying Chinese State Councilor Tang Jiaxuan told them a second round of talks can be expected next month.

On Sunday, in a televised interview aired on Japan's quasi-official NHK network, U.S. Secretary of State Colin Powell said he is confident a second round of talks will be held in the "not-too-far future."

Tensions have been high since the United States announced in October of 2002 that North Korea had admitted having a secret uranium enrichment program in violation of international atomic accords.